Singulation of optical waveguide materials
Methods for singulating an optical waveguide material at a contour include directing a first laser beam onto a first side of the optical waveguide material to generate a first group of perforations in the optical waveguide material. A second laser beam is directed onto a second side of the optical waveguide material to generate a second group of perforations in the optical waveguide material. The second side is opposite the first side. The first group of perforations and the second group of perforations define a perforation zone at the contour. A third laser beam is directed at the perforation zone to singulate the optical waveguide material at the perforation zone.
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This application claims priority to U.S. application Ser. No. 17/126,574, filed on Dec. 18, 2020, which claims priority to U.S. Application Ser. No. 62/951,261, filed on Dec. 20, 2019, which are incorporated by reference herein in their entity.
TECHNICAL FIELDThis disclosure relates to singulating optical waveguide materials.
BACKGROUNDTraditional methods that use milling or water jets to cut optical substrates can cause stresses in the substrate. Excess substrate stress can cause pieces of the substrate to separate along paths that are not in accordance with the singulation program.
SUMMARYInnovative aspects of the subject matter described in this specification include methods, apparatus, and systems for singulating an optical waveguide material at a contour. A first laser beam is directed onto a first side of the optical waveguide material to generate a first group of perforations in the optical waveguide material. A second laser beam is directed onto a second side of the optical waveguide material to generate a second group of perforations in the optical waveguide material. The second side is opposite the first side. The first group of perforations and the second group of perforations define a perforation zone at the contour. A third laser beam is directed at the perforation zone to singulate the optical waveguide material at the perforation zone.
Among others, the benefits and advantages of the embodiments disclosed herein include the manufacture of optical waveguides for monocular or binocular headsets having enhanced visual qualities and performance compared to traditional methods. The embodiments provide the generation of complex shapes having demanding geometries for critical optical alignment from birefringent substrates of varying thickness and indices of refraction. The incising of a localized region surrounding a critical area of interest provides reduced wafer-level stress compared to traditional methods. Thus stress cracks and fractures along the preferential crystalline internal structure are reduced compared to traditional methods, and the process yield is increased.
The details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other potential features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.
The system 100 further includes an imprint lithography flexible coated resist template 112 that is coupled to one or more rollers 114a, 114b, 114c, 114d, 114e. The rollers 114a, 114b, 114c, 114d, 114e provide movement of the flexible coated resist template 112. Such movement can selectively provide different portions of the flexible coated resist template 112 in superimposition with the substrate 102. In some embodiments, the flexible coated resist template 112 includes a patterning surface that includes a group of features, e.g., spaced-apart recesses and protrusions. The patterning surface can define any original pattern that defines the basis of a pattern to be formed on substrate 102. In some embodiments, the flexible coated resist template 112 is coupled to a template chuck, e.g., a vacuum chuck, a pin-type chuck, a groove-type chuck, or an electromagnetic chuck.
The system 100 can further include a fluid dispenser 120. The fluid dispenser 120 can be used to deposit a polymerizable material on the substrate 102. The polymerizable material can be positioned upon the substrate 102 using drop dispense, spin-coating, dip coating, chemical vapor deposition, physical vapor deposition, thin film deposition, or thick film deposition. The system 100 can further include an energy source 122 to direct energy (such as from a laser beam) towards the substrate 102. In some embodiments, the rollers 114 and the air bearing 106 are configured to position a desired portion of the flexible coated resist template 112 and the substrate 102 in a desired positioning. The system 100 can be regulated by a controller in communication with the air bearing 106, the rollers 114, the fluid dispenser 120, or the energy source 122, and may operate on a computer readable program stored in a memory.
The laser 200 illustrated in
Prior to singulating the optical waveguide material 212, a first laser beam (such as the laser beam 204) is directed from a first laser (such as the laser 200) onto the optical waveguide material 212 to incise a set of fiducial markers 232 in the optical waveguide material 212. In some embodiments, the first laser beam 204 is directed onto the optical waveguide material 212 by the laser 200. In other embodiments, the first laser beam 204 is directed by a controller, the robot 100, or a motor. In some embodiments, the first laser 200 is a diode-pumped laser. For example, the first laser 200 can be a solid-state laser that uses a diode-pumped, mode locked system with ultra-short pulses and a high pulse energy. In some embodiments, a wavelength of the first laser beam 204 is in a range from 750 nm to 1500 nm.
The set of fiducial markers 232 are in a spaced relationship with the contour 224 and are used as points of reference or a measure. For example, the computer image used for manufacturing an eyepiece or other optical device can define the fiducial markers 232 to monitor the placement of the optical waveguide material 212 and align the optical waveguide material 212 with the first laser 200. The contour 224 and fiducial markers 232 can be programmed such that the set of fiducial markers 232 are in a spaced relationship with the contour 224, defined by coordinates and a predefined separation between the contour 224 and the fiducial markers 232. The contour 224 and fiducial markers 232 together define a singulation pattern or program for manufacturing an optical device.
To singulate the optical waveguide material 212 at the contour 224, the first laser beam 204 is directed from the first laser 200 onto a first side 208 of the optical waveguide material 212. The first laser beam 204 generates a first set of perforations 220 in the optical waveguide material 212. The first set of perforations 220 is illustrated and described in more detail with reference to
In some embodiments, the first laser beam 204 generates the first set of perforations 220 by ablating the first portion of the optical waveguide material 212 at the contour 224, such that the first set of perforations 220 extend through the optical waveguide material 212 from the first side 208 to the second side 216, as illustrated and described in more detail with reference to
In some embodiments, a focus offset of the first laser beam 204 is in a range from −0.3 mm to 0.3 mm. The focus offset of the first laser beam 204 is sometimes referred to as the z-offset. The focus offset setting of the first laser beam 204 is used to direct (focus) the first laser beam 204 onto the contour 224. In some embodiments, a number of pulses per burst of the first laser beam 204 is in a range from 4 to 15. The number of pulses per burst can be adjusted by the system 250, which is illustrated and described in more detail with reference to
A computer numerically controlled speed of the first laser beam 204 can be in a range from 4 m/minute to 15 m/minute. The computer numerically controlled speed of the first laser beam 204 can be adjusted by a singulation program executed by the system 250 in
The optical waveguide material 212 is rotated about an axis 228 in a plane of the optical waveguide material 212, such that a second side 216 of the optical waveguide material 212 faces a second laser 236. For example, the plane of the optical waveguide material 212 can be the plane of the first side 208. The second side 216 of the optical waveguide material 212 is opposite the first side 208. The optical waveguide material 212 can be rotated by a motor 254, of the system 250 in
A second laser beam is emitted by the second laser 236 and directed onto the second side 216 of the optical waveguide material 212 to generate a second set of perforations 404 in the optical waveguide material 212. The second set of perforations 404 is illustrated with reference to
A third laser beam is emitted by the third laser 240 and directed at the perforation zone 412 to singulate the optical waveguide material 212 at the perforation zone 412. In some embodiments, the third laser 240 is a carbon dioxide (CO2) laser. In other embodiments, the third laser 240 is a radio frequency (RF)-excited, pulsed CO2 separation laser. In some embodiments, the third laser beam includes infrared light having a wavelength in a range from 5 μm to 15 μm. In some embodiments, a focus offset range of the third laser beam is less than 5 mm. The focus offset or z-offset of the third laser beam is used to direct (focus) the third laser beam onto the perforation zone 412 for singulating the optical waveguide material 212. In some embodiments, a frequency of the third laser beam is in a range from 10 kHz to 20 kHz. The frequency of the third laser specifies the number of laser pulses per second. The amount of energy per photon decreases as the wavelength of the third laser beam increases. In some embodiments, a power of the third laser beam is in a range from 10 W to 35 W. The rate of singulation of the optical waveguide material 212 increases as the power of the third laser beam increases.
In some embodiments, the stage 108 illustrated in
A first laser beam 204 is directed from a first laser 200 onto a first side 208 of the optical waveguide material 212 to incise boundary markers 316, 320 on the first side 208. The first laser 200, the first laser beam 204, and the first side 208 are illustrated and described in more detail with reference to
To singulate the optical waveguide material 212 at the contour 224, the first laser beam 204 is directed from the first laser 200 onto the first side 208 of the optical waveguide material 212 to generate the first set of perforations 220. A motor 254 is configured to rotate the optical waveguide material 212 about an axis 228 in a plane of the optical waveguide material 212, such that the second side 216 of the optical waveguide material 212 faces the second laser 236. The axis 228, the second side 216, and the second laser 236 are illustrated and described in more detail with reference to
Responsive to rotating the optical waveguide material 212, the motor 254 positions the optical waveguide material 212, such that the fiducial markers 232 are in a spaced relationship with the contour 224. The fiducial marker 232 is illustrated and described in more detail with reference to
A second laser beam is directed from the second laser 236 onto the second side 216 of the optical waveguide material 212. The second laser beam generates a second set of perforations (for example, the second set of perforations 404, illustrated and described in more detail with reference to
A third laser beam is directed from a third laser (for example, the third laser 240, illustrated and described in more detail with reference to
The second laser beam is directed from the second laser 236 onto the second side 216 of the optical waveguide material 212 to generate the second set of perforations 404 in the optical waveguide material 212. The second laser 236 and second side 216 are illustrated and described in more detail with reference to
The first set of perforations 220 and the second set of perforations 404 define a perforation zone 412 at the contour 224. The perforation zone 412 is located between the first set of perforations 220 and the second set of perforations 404. The first laser beam 204 and second laser beam are directed at the optical waveguide material 212, such that the perforation zone 412 aligns with the contour 224 and the optical waveguide material 212 can be singulated at the contour 224.
The optical waveguide material 212 is singulated at the contour 224 by directing a third laser beam from the third laser 240 at the perforation zone 412. The third laser 240 is illustrated and described in more detail with reference to
In step 504, a first laser beam 204 from a first laser is directed onto a first side 208 of the optical waveguide material 212 to generate a first set of perforations 220 in the optical waveguide material 212. The first laser 200, first laser beam 204, first side 208, and first set of perforations 220 are illustrated and described in more detail with reference to
In step 508, a second laser beam from a second laser 236 is directed onto a second side 216 of the optical waveguide material 212 to generate a second set of perforations 404 in the optical waveguide material 212. The second laser 236 and second side 216 are illustrated and described in more detail with reference to
In step 512, a third laser beam is directed from a third laser 240 at the perforation zone 412 to singulate the optical waveguide material 212 at the perforation zone 412. The third laser 240 is illustrated and described in more detail with reference to
In additional embodiments, the second laser is configured to emit the second laser beam to generate the second set of perforations, such that a spacing between the first set of perforations and the second set of perforations is less than a specified accuracy tolerance. The specified accuracy tolerance is less than 25 μm and the spacing is less than 15 μm.
In some embodiments, the third laser is configured to emit the third laser beam to singulate the optical waveguide material by heating the optical waveguide material at the perforation zone to expand the first set of perforations and the second set of perforations.
In some embodiments, the first laser and the second laser are the same, and a frequency of the first laser is in a range from 100 kHz to 300 kHz.
In some embodiments, the contour defines a shape of a first piece of the optical waveguide material to be singulated from a second piece of the optical waveguide material.
In some embodiments, the optical waveguide material includes a crystalline material having a refractive index greater than 1.6.
In some embodiments, the third laser is a CO2 laser, and a wavelength of the third laser beam is in a range from 5 μm to 15 μm.
In some embodiments, the first laser is a diode-pumped laser, and a wavelength of the first laser beam is in a range from 750 nm to 1500 nm.
In some embodiments, the optical waveguide material is less than 1 mm thick and each perforation of the first set of perforations and the second set of perforations has a maximum diameter less than 10 μm.
In some embodiments, a distance between a consecutive pair of perforations of the first set of perforations is in a range from 3.5 μm to 8.3 μm.
In some embodiments, a focus offset of the first laser beam is in a range from −0.3 mm to 0.3 mm, and a number of pulses per burst of the first laser beam is in a range from 4 to 15.
In some embodiments, a power of the first laser beam is in a range from 45 W to 55 W, and a computer numerically controlled speed of the first laser beam is in a range from 4 m/minute to 15 m/minute.
In some embodiments, a wavelength of the third laser beam is in a range from 5 μm to 15 μm, and a focus offset range of the third laser beam is less than 5 mm.
In some embodiments, a frequency of the third laser beam is in a range from 10 kHz to 20 kHz, and a power of the third laser beam is in a range from 10 W to 35 W.
In the foregoing description, embodiments have been described with reference to numerous specific details that may vary from implementation to implementation. The description and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
Claims
1. A method for manufacturing an optical eyepiece, the method comprising:
- directing a first laser beam from at least one laser onto a first side of an optical waveguide material for the optical eyepiece, wherein the first laser beam generates a first plurality of perforations in the optical waveguide material, wherein the first plurality of perforations extend through the optical waveguide material from the first side of the optical waveguide material to a second side of the optical waveguide material;
- directing a second laser beam from the at least one laser onto the second side of the optical waveguide material to generate a second plurality of perforations in the optical waveguide material, wherein the second side is opposite the first side, and wherein the first plurality of perforations and the second plurality of perforations define a perforation zone; and
- directing a third laser beam from the at least one laser at the perforation zone to singulate the optical waveguide material at the perforation zone.
2. The method of claim 1, wherein the first laser beam and the second laser beam are sent from a same laser of the at least one laser.
3. The method of claim 1, wherein the first laser beam and the third laser beam are sent from different types of lasers.
4. The method of claim 1, wherein at least one of the first laser beam and the second laser beam is sent from a diode-pumped laser.
5. The method of claim 1, wherein the third laser beam is sent from a carbon dioxide laser.
6. The method of claim 1, wherein the optical waveguide material has a refractive index greater than 1.6.
7. The method of claim 1, wherein the first laser beam generates the first plurality of perforations by chemically altering a first portion of the optical waveguide material, the first portion corresponds to the first plurality of perforations, the second laser beam generates the second plurality of perforations by chemically altering a second portion of the optical waveguide material, and the second portion corresponds to the second plurality of perforations.
8. The method of claim 1, wherein the first laser beam generates the first plurality of perforations by ablating a first portion of the optical waveguide material, the first portion corresponds to the first plurality of perforations, the second laser beam generates the second plurality of perforations by ablating a second portion the optical waveguide material, and the second portion corresponds to the second plurality of perforations.
9. The method of claim 1, wherein singulating the optical waveguide material at the perforation zone comprises heating the optical waveguide material at the perforation zone to expand the first plurality of perforations and the second plurality of perforations.
10. The method of claim 1, further comprising rotating the optical waveguide material about an axis in a plane of the optical waveguide material, such that the second side faces the second laser beam.
11. The method of claim 1, further comprising:
- incising, by the first laser beam, a plurality of fiducial markers in the optical waveguide material; and
- using the plurality of fiducial markers to align the optical waveguide material with a laser generating the first laser beam.
12. An apparatus for manufacturing an optical eyepiece, the apparatus comprising:
- at least one laser that is configured to:
- emit a first laser beam onto a first side of an optical waveguide material for the optical eyepiece such that the first laser beam generates a first plurality of perforations in the optical waveguide material, wherein the first plurality of perforations extend through the optical waveguide material from the first side of the optical waveguide material to a second side of the optical waveguide material;
- emit a second laser beam onto the second side of the optical waveguide material to generate a second plurality of perforations in the optical waveguide material, wherein the second side is opposite the first side, and the first plurality of perforations and the second plurality of perforations define a perforation zone; and
- emit a third laser beam at the perforation zone to singulate the optical waveguide material at the perforation zone.
13. The apparatus of claim 12, wherein the first laser beam and the second laser beam are emitted from a same laser.
14. The apparatus of claim 12, wherein the first laser beam and the second laser beam are emitted from a same type of laser.
15. The apparatus of claim 12, wherein the first laser beam and the third laser beam are emitted from different types of lasers.
16. The apparatus of claim 12, wherein at least one of the first laser beam and the second laser beam is emitted from a diode-pumped laser.
17. The apparatus of claim 12, wherein the third laser beam is sent from a carbon dioxide laser.
18. The apparatus of claim 12, wherein the first laser beam generates the first plurality of perforations by chemically altering a first portion of the optical waveguide material, the first portion corresponds to the first plurality of perforations, the second laser beam generates the second plurality of perforations by chemically altering a second portion of the optical waveguide material, and the second portion corresponds to the second plurality of perforations.
19. The apparatus of claim 12, wherein the first laser beam generates the first plurality of perforations by ablating a first portion of the optical waveguide material, the first portion corresponds to the first plurality of perforations, the second laser beam generates the second plurality of perforations by ablating a second portion the optical waveguide material, and the second portion corresponds to the second plurality of perforations.
20. The apparatus of claim 12, further comprising a motor operatively coupled to the optical waveguide material and configured to rotate the optical waveguide material about an axis in a plane of the optical waveguide material, such that the second side of the optical waveguide material faces the second laser beam.
21. The method of claim 1, wherein the second plurality of perforations extend through the optical waveguide material from the second side of the optical waveguide material to the first side of the optical waveguide material.
22. The method of claim 1, wherein a spacing between the first plurality of perforations and the second plurality of perforations is less than a specified accuracy tolerance.
23. The method of claim 22, wherein the specified accuracy tolerance is based on a computer numerical control (CNC) laser module accuracy tolerance or based on a CNC stage accuracy tolerance.
24. The apparatus of claim 12, wherein the at least one laser is configured to generate the second plurality of perforations so that the second plurality of perforations extend through the optical waveguide material from the second side of the optical waveguide material to the first side of the optical waveguide material.
25. The apparatus of claim 12, wherein the at least one laser is configured to generate the first plurality of perforations and the second plurality of perforations so that a spacing between the first plurality of perforations and the second plurality of perforations is less than a specified accuracy tolerance.
26. The apparatus of claim 25, wherein the specified accuracy tolerance is based on a computer numerical control (CNC) laser module accuracy tolerance or based on a CNC stage accuracy tolerance.
27. A method for manufacturing an optical eyepiece, the method comprising:
- directing a first laser beam from at least one laser onto a first side of an optical waveguide material for the optical eyepiece, wherein the first laser beam generates a first plurality of perforations in the optical waveguide material;
- directing a second laser beam from the at least one laser onto a second side of the optical waveguide material to generate a second plurality of perforations in the optical waveguide material, wherein the second side is opposite the first side, and wherein the first plurality of perforations and the second plurality of perforations define a perforation zone;
- directing a third laser beam from the at least one laser at the perforation zone to singulate the optical waveguide material at the perforation zone;
- incising, by the first laser beam, a plurality of fiducial markers in the optical waveguide material; and
- using the plurality of fiducial markers to align the optical waveguide material with a laser generating the first laser beam.
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Type: Grant
Filed: Dec 6, 2021
Date of Patent: Jul 4, 2023
Patent Publication Number: 20220091336
Assignee: Magic Leap, Inc. (Plantation, FL)
Inventors: Arturo Manuel Martinez, Jr. (Austin, TX), Vikramjit Singh (Pflugerville, TX), Michal Beau Dennison Vaughn (Round Rock, TX), Joseph Christopher Sawicki (Austin, TX)
Primary Examiner: Chad H Smith
Application Number: 17/457,860
International Classification: B23K 26/364 (20140101); G02B 6/132 (20060101); G02B 6/138 (20060101); B23K 26/359 (20140101); B23K 26/38 (20140101); G02B 6/12 (20060101); C03B 33/02 (20060101);